Published online by Cambridge University Press: 20 November 2018
Let $G$ be an infinite discrete group and let
$\beta G$ be the Stone-Čech compactification of
$G$ . We take the points of
$\beta G$ to be the ultrafilters on
$G$ , identifying the principal ultrafilters with the points of
$G$ . The set
$U\left( G \right)$ of uniform ultrafilters on
$G$ is a closed two-sided ideal of
$\beta G$ . For every
$p\,\in \,U\left( G \right)$ , define
${{I}_{p}}\,\subseteq \,\beta G$ by
${{I}_{p}}\,=\,{{\bigcap }_{A\in p}}\text{cl}\left( GU\left( A \right) \right)$ , where
$U\left( A \right)\,=\,\left\{ p\,\in \,U\left( G \right)\,:\,A\in \,p \right\}$ . We show that if
$\left| G \right|$ is a regular cardinal, then
$\left\{ {{I}_{p}}\,:\,p\,\in \,U\left( G \right) \right\}$ is the finest decomposition of
$U\left( G \right)$ into closed left ideals of
$\beta G$ such that the corresponding quotient space of
$U\left( G \right)$ is Hausdorff.